Thermoregulating textiles and fibrous materials for passive radiative cooling functionality

Developing thermoregulating textiles based on passive radiative cooling strategies has recently attracted considerable attention as an emerging means of providing localised thermoregulation for wearers. This cooling mechanism not only has been used to enhance the thermal comfort in both indoor and outdoor spaces, but it has also been regarded as one of the promising methods of reducing dependency on energy-intensive air conditioning systems. This article reviews recent advances in developing fibrous structures with passive radiative cooling functionality including mid-infrared (MIR) transparent textiles, and textiles with passive daytime radiative cooling (PDRC) effect. The fundamental working mechanisms, fabrication methods, and reported performances of these functional textiles are reviewed and compared. Specific attention is paid to recent technological advances in obtaining the radiative cooling functionality via conventional manufacturing methods including coating, fibre spinning, nanofibres electrospinning, weaving/knitting of fabrics, and nonwovens. Passive radiative cooling mechanisms of several natural species are also discussed, to guide the development of novel thermoregulating textiles. This article provides a comprehensive review of the status of passive radiative cooling technology in textiles and delineates some possible pathways for future improvements with potential applications in sportswear, protective clothing, and other wearable textiles.